The present invention relates to an improved motion generating mechanism for a music box which is comprised of a driving wheel associated with the playing roller of the music box; and a crank arm having a cam board mounted thereto and eccentrically secured to the driving wheel is provided with an engagement protrusion at each end thereof. A supporting base having a swing arm which is provided with an elongated guide groove is pivotally fixed to a securing seat mounted to the mounting plate of the music box and to the base plate of an outer case respectively. Each engagement protrusion of the crank arm is slidably engaged with the guide groove of each swing arm so that the rotation of the driving wheel will cause the crank arm to accordingly move, making the supporting bases to be pivotally operated in synchronism. To each supporting base is attached a mounting pole on which is disposed a decoration article whereby the motion of the crank arm can make the decoration articles to act in a fascinating manner. The cam board is in abutment against an abutment disc on which is disposed an actuation pole so as to make an decoration article attached thereto to move also in synchronism with the other decoration articles moved with the music played by the music box, making the motion of the decoration articles more interesting.
Referring to FIG. 1, a conventional music box having a mounting plate 11 is disposed on a base plate 10 of an outer case. A mounting pole 21 led through the upper lid 20 of the outer case is provided with a follower base 22 at the bottom end thereof. A spring tightening unit 12 mounted to the mounting plate of the music box is able to drive a playing roller 13 to move when tightened. There are a plurality of protrusion points disposed on the playing roller 13 which can actuate a plurality of music producing strips 14 having a different length to generate music.
As further shown in FIG. 2, a connection rod 15 having a driving wheel 16 eccentrically disposed at each end thereof that can make the follower base 22 disposed at the bottom end of the mounting pole 21 to be actuated up and down and circularly in synchronism with the played music so as to make the decoration articles dancingly moved in an interesting manner.
However, the simple structure of the prior art driving mechanism can only produce simple motion without too much variation, so it becomes less competitive in a fast changing consumer market.
To overcome the above cited problem, the present inventor has worked out an improved motion generating mechanism which can produce complex motions in synchronism with a played music.